NIHAO III: The constant disc gas mass conspiracy

G. S. Stinson, A. A. Dutton, L. Wang, Andrea Maccio, J. Herpich, J. D. Bradford, T. R. Quinn, J. Wadsley, B. Keller

Research output: Contribution to journalArticle

Abstract

We show that the cool gas masses of galactic discs reach a steady state that lasts many Gyr after their last major merger in cosmological hydrodynamic simulations. The mass of disc gas, Mgas, depends mostly upon a galaxy virial mass and halo's spin, and less upon stellar feedback. Haloes with low spin have high star formation efficiency and lower disc gas mass. Similarly, lower stellar feedback leads to more star formation so the gas mass ends up being nearly the same regardless of stellar feedback strength. Rather than regulating cool gas mass, stellar feedback regulates the mass of stars that forms. Even considering spin, the Mgas relation with halo mass, M200 only shows a factor of 3 scatter. The simulated Mgas-M200 relation shows a break at M200 = 2 × 1011M⊙ that corresponds to an observed break in the Mgas-M* relation. The galaxies that maintain constant disc masses share a common halo gas density profile shape in all the simulated galaxies. In their outer regions, the profiles are isothermal. Where the profile rises above n = 10-3 cm-3, the gas readily cools and the profile steepens. Inside the disc, rotation supports gas with a flatter density profile. Energy injection from stellar feedback provides pressure support to the halo gas to prevent runaway cooling flows. The constant gas mass makes simpler models for galaxy formation possible, either using a 'bathtub' model for star formation rates or when modelling chemical evolution.

Original languageEnglish (US)
Pages (from-to)1105-1116
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume454
Issue number1
DOIs
StatePublished - Jan 1 2015

Fingerprint

gases
gas
halos
profiles
galaxies
star formation
chemical evolution
galactic evolution
gas density
star formation rate
stellar mass
merger
hydrodynamics
injection
stars
cooling
modeling
simulation
energy

Keywords

  • Galaxies: formation
  • Galaxies: ISM
  • Hydrodynamics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Stinson, G. S., Dutton, A. A., Wang, L., Maccio, A., Herpich, J., Bradford, J. D., ... Keller, B. (2015). NIHAO III: The constant disc gas mass conspiracy. Monthly Notices of the Royal Astronomical Society, 454(1), 1105-1116. https://doi.org/10.1093/mnras/stv1985

NIHAO III : The constant disc gas mass conspiracy. / Stinson, G. S.; Dutton, A. A.; Wang, L.; Maccio, Andrea; Herpich, J.; Bradford, J. D.; Quinn, T. R.; Wadsley, J.; Keller, B.

In: Monthly Notices of the Royal Astronomical Society, Vol. 454, No. 1, 01.01.2015, p. 1105-1116.

Research output: Contribution to journalArticle

Stinson, GS, Dutton, AA, Wang, L, Maccio, A, Herpich, J, Bradford, JD, Quinn, TR, Wadsley, J & Keller, B 2015, 'NIHAO III: The constant disc gas mass conspiracy', Monthly Notices of the Royal Astronomical Society, vol. 454, no. 1, pp. 1105-1116. https://doi.org/10.1093/mnras/stv1985
Stinson, G. S. ; Dutton, A. A. ; Wang, L. ; Maccio, Andrea ; Herpich, J. ; Bradford, J. D. ; Quinn, T. R. ; Wadsley, J. ; Keller, B. / NIHAO III : The constant disc gas mass conspiracy. In: Monthly Notices of the Royal Astronomical Society. 2015 ; Vol. 454, No. 1. pp. 1105-1116.
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